Centralized control system



Jan. 8, 1929.

C. H. SMQOT CENTRALI'ZED CONTROL SYSTEM vFiled April '7, 1927 CMPRESSED Sl/Pfl? Afl/w72?? CONTROLLER fno-{UNA- lv e' S70/ffl? W50 REElAMRJ IN VEN TOR. CHARLEJ d. 644007 BY l v TORNEYS.

Patented i Jan. s, 1929.

UNITED STA '1,698,6311- Tes PATENT orifice.

I CHARLES H. SMOOT, OF MAPLEWOOD, NEW- JERSEY.

CETBALIZED CONTROL SYSTEM.'

Application .med April 'z ,i-sav. serial- No. 181,713.

This inventionirelates to a controlsystem for governing the output of industrial rol v system.

ducing plants where such output is contro led by` amaster regulator which automatlcally correlates the various controls of the elements contributing to the common output. In my Reissue Patent No. 16,507 of December 21,. 1926, :I have described such a master control The present invention is especially adapted to`large plants where itis desirable to 'divide l' the units into groups that may, as desired, be

controlled differently from other groups, orl

cut; out from the master control, and comprises the combination of section master controllers anda super master controller, wluch has means responsive to the fluctuations of a function of the common output of the plant i; to roduce a controllingforce variable with l th 'ri'atioris of said function and communiv 7catingme'ans leading from the super master controller vto the section master controllers,

whereby, the Vlatter `will be varied'. correlatively with the response of the super master controller to the requirements.

The invention further comprises means asfsociated with vthe vsuper master controller for introducing a compensating element whereby after'a change in the function to be regulated persists, a change will be made in the adjust ments of the regulator so as to compensate for lthe change while allowing the lfunction tobe,

returned to normal.

The lnvention further comprises means` for insuring the uninterrupted operation of'the l controlling system in case of failure of vsome of the communicating means to and from the controllers. In the present invention this is 1 may, for example, bethe mam -steam pipe .of a power plant.` From this 'ipe Vac conduit 2` .leads to a chamber 3"whic is closed by-,a dipahragmfi, therod of which is connected At 1 is showna. main supply pipe which to a lever 6, pivoted at 7 and hayinga loading device 8 which is shown as a spring. The

lever 6 is connected throu h rod 9 with a cup valve 10 adapted to close t e escape from pipe 11 which connects with a chamber 12 through 'a valve 13. Chamber 12 is adapted to con- 'tam compressed air supplied thereto through a needle valve 13 from a pipe 14 connected to a source of compressed air supply. The mechanism thus described has the function of vvarylng the pressure in-chamber 12 inversely as the pressure in pipe 1, the variation in chamber 12, however,'being at a much greater ratio than the variation in pipe 1.- `A slight fall, for example, in pressure-in pipe l, al

lowing air to escape with less rapidity past the cup valve 10,r increases to an exaggerated degree, the pressure in chamberv 12. The mechanismy forms a means that is responsive to al change of a function, in'this case the pressure of the fluid flowing in pipe 1, which change is an indication of a change inthe demandfor production of the common output. From the chamber 12,.a number of communicat-ing means, such as pipes 15, lead to other chambers forming part-s of other regulating apparatus designed to each control a separate section of elements that are contributing to the product supplied 'to pipe 1.- At

16 isshown such a chamber which 1s similar to that shown at'12, b'ut instead of having the fixed loading such as 8, has its loading device or lever 17 under the influence of the communicating means 15 from chamber 12.

As shown in the drawing, I prefer to make these communicating means in duplicate as,

'for example, two pipes leading from chamber 12 to chambers 18- having diaphragme 19 that bear with equal force on the opposite at 21 tothe end of the load' lever or device '17, the latter controlling a cup valve 22 which in turn controls the esca e of air from chamber 16, the said cham r being supplied through a needle valve 23 by pipe 24 leading tothe source of compressed'air supply. The mechanism just describedl will cause the pressure inV chamber 16 to respond proportionately to the pressure in chamber 412.

Chamber 16- isone of a plurality of master` controllers each having means for controllin o5 l ends of the lever 20, pivoted in the middle.

individualV elements contributing to the ro uct in pipev 1. For example, thereare s own V l leading from chamber J16 through -needle valves 25, cqmmunicatixnc; means such-,as pipes26 leadin'gto local cgptrols which will regulate the elements which are contributory to the product in pipe 1. In the case of a Steam generating plant, these commumcating means would control individually, for example, the forced draft, lthe fuel feed, stack damper, boiler feed water, or any. other elements the supply of which should vary in accordance with the requirements'. The fluctuations in the requirements. of -the common output as, for example, the demandV for steam will be indicated by a functionv of the steam such as a fall or rise of pressure in pipe 1 so that the fluctuation in de.

mand will, bythe variation brought about thereby in chamber 12, cause a similar variation to occur in all of the subsidiary control chambers 1d, which will in proper manner pass on the demand to the various local controls whose `dutygit is toV vary the supply' of the elements entering into the common out- A put in pipe 1. By making the communicatingmeans in du licate, the failure as by break age of any o the communicating means, will not cause the apparatus to cease to function, for' if thev pressure is relieved from one of the diaphragms 19 by the failure ofthe supplv V ipe leading thereto, such diaphragm will e pushed to its limit of play and the work of regulation will be entirely taken up by the remaining diaphragin 19 which, acting now with twice the leverage, will, with the same amount of pressure coming through chamber 12, give the same effect of load upon the device 17 as if bot-h 4dia-phragms 19 were acting conjointly. Such a -duplication Yof communicating conductors or conduits may In the operation ofthe apparatus, when a change takes place in the pipe 1, the lever 6 will move, causing a .change in the openlng'.

of valve 10 to bring about a change' of presphragm 3 are such asto maintain abalance v thereupon. The change in pressure ichamber 12 eiect's :the section controllers and through them the local Vcontrols to v'bring about a change inthe supply of elements f tending to prevent further change in the Vconditlon in pipe 1. The pressure in pipe 12 would have therefore so far as the operation of the apparatus above described is concrned, a definite valueffo'r each setting of of the condition in pipe 1.

I prefer, however, to associate ,with the, super mastercontroller, means forintroduc ing an compensating element whereby after 'a change in the function to be regulated perssts, 'a change will be. made 'inf the adj-ustments of .the regulator so astol compensate for the change while allowing the functionto the lever-6 corresponding to definite values be returned to normal with Ithe result `that the 1 value of the controlling force depends not upon the `actual value yof the function to be regulated, but upon the magnitude of the changes from upon the duration of these variations from' normal. Such associated compensating means forms no part of my present invention as it forms the subject matter of my copendapplication, Serial No. 143,414, filedOcto- .evidentl be used in any part of thestem.. mg

y Sy ber 22, 1926. I have, however, shown at 33 At 27 is. shown a release valve similar to the one shown at 10 which, b means of pipe 28 and valve 29, may enab e an operator through screw 30 to vary the load 31 to control manually the pressure in chamber 12 and thus give the means of manuall operating- In suc cases, the

the controlling system. valve 13 in pipe11n would be closed.- A similar manual control may be installed for each of the chambers '16S of the` section masters as vshown at32. The chambers 16 and their connected apparatus form section' master controllers, each having control of .a section of the plant, while thechamber 12 .and its com necting mechanism forms a super master controller for correlatively regulating all the section master controllers. The super master alone is made responsive tothe requirements of the common output in pipe 1', and

' by its `communicating means, connecting it -p such compensating means` as illustrating the preferred form of my centralized control system. The device 33 comprises a casing dlvided into two compartments b a artition 34 in which is an orifice regalata le y an adjusting screw 35.v Mercury or other fluid in the chamber is carried at such a level as to cover the opening in the partition. One section -of the chamber has' a diaphragm 36' whereby. the weight of the mercury and the pressure transmitted'to it is added to the loadi ing of lever 6. The other chamber ha's a' pipe 37 in communication with the chamber` 12.

rma'l occurring therein and The pressure upon diaphragm 36 acts, upon a lever 6 through the rod 5 to which the idiaph'ragzmisattached.n The location of the ivot 7 is so-chosen that the turning moment odered to thelxer '6 by th presllrefpon .dia-

hragm' 1s practica u an --o 'te Vto that 'oered'by the miic-,IEW

--If the pressure in pipe for instance-indicating a need for increase in the supply of element, an unbalance occurs upon the lever '6 in a directionto close valve 10 to increase the pressure in chamber' 12. 'I 'he increase .in .pressure'in chamber 12 amber '12 through cup 1() when thesepressures l 30 boilers.

J i will reactimmediately upon the lever 6l p through the cup 10 but only after a definite.

t-ime interval will this `change be felt` upon diaphragm 36. Thepressure in. pipe 1 will gradually increase due to the increased supply of elements called for by the increase in pressure inchamber 12, and, at the same time the pressure upon diaphragm 36 will increase to the lvalue of that in chamber 12 by the forcing of liquid through the orifice. Preferably the equallzation of pressures upon diaphragm 36 and cup 10 Will be completed at the monient that the pressure in pipe v1 returns to the desired value as determined by springs 8. The element 33 thus permits the pressure in vchamber 12 to be independent of the actual pressure in pipe lfbut to be dependent uponthe direction and duration of the changes from normal of this pressure.

It will be apparent that my control system comprisinga super master and the various section masters, when applied for instance to the control of a boiler plant, permits the control rof the Whole plant from a central 'point` If it isV desired to cut out a certain group of boilers, it is only necessary to close` the connections at the super master tothe communicating lines leading'to the section master controlling that particular 'group of Similarly the different groups of boilers maybe operated nat different ratings by proper adjustment at the super master. Any group may readily be transferred from automatic to manual control or the entire plant may be placed under manual control lduits or conductors are intended to bedirectly from the super master if desired.

` While I have shown the application of the invention to anexample more particularly adapted for steam production in a power plant, it Will be obvious that in its broader aspects, the invention is equally applicable to the regulation .and control of any industrial plant in which a number of variablel elements are made to contribute to a common output. Y y

In the example above described, the communicating means to and from the controllers are shown as pipes conveying compressed air.

The medium for conveying the force mayy equally Well be electricity or any other suit- -able medium and the Words fluid and conused in their broadest sensei'n the following output, comprisinga super master controller control system adapted \to-. regulate.

sure and regulatableV to vary the pressure or said fluid,- a plurality of section master controllers also connected to asource of fluid under pressure, and means cooperatively relating the supermaster to the section masters to vary the fiuid pressure of each section master responsively Ato variations of thesupermaster pressure.

4. A control system adaptedto regulate various elements contributing tov a common output,.compri'sing a super master controller, a plurality of section master controllers, means at each section master for controlling the said variable elements, loading means for ^cach of said section master controllers, the super master controller having means responsive to the fluctuations of a .tunctionvof the common output, lloading means for the same and communicatingmeans leading from the super master controller to the section master controllers whereby the loadings of the section master controllers xare rendered .responsive' to changes in the super master controller engendered by the fluctuations ofthe common output.- y 5. A control system adapted to regulate various elements contributing to a common output, comprising a super master controller, a plurality of 'section master controllers, means at each section master for controlling the said variable elements, loading means for lim each of said section master controllers, the

super master controller having means responsive to the fluctuations of a function of the common out-put, loading means for the same, .and communicating means leading from the super master controller to the section master controllers whereby the loadings of the section master controllers are rendered responsive to changes inthe super master controller engendered by the iuctuations of the common output, with time delay means connected to the loading means oi? the super master cfmtroller to permit immediate response to fluctuations of the common loutput and after a predetermined lapse of 'time to change the Said loading to meet the nevvrequirements.

6. A control system adapted toregulate vvarious elements contributing to a common output,.comprising a super master; controller, a plurality. Iof section master, controllers, means ateach section master for controlling the said variable elements, loading4 means for each of said section master controllers, the-super master controller havingl means lll' sov

responsive to the fluctuations cfa function of the common output, loading means for same and communicating means leading from the super master controller to the section master controllers whereb the loadings of, the section master controllers are rendered responsive to changes in the super master controller engendered by the fluctuations of the common output, with manual control means at the super master, and means for cutting oil' the means responsive to the. requirements and substituting the manual control means.

7. A control system adapted to regulate various elements contributing to a common output, comprising a super master controller,

a plurality of section master controllers, means at each section master for controlling the said variable elements, loadingmeans for each of said section master controllers, the super master controller having means responsive to the Afluctuations of a function of the common output, loading meansI for same and communicating means leading from the super master controller to the section master controllers whereby the loading of the section master controllers is rendered responsive to changes in the super master controller engendered by the fluctuations of the common output, with manual control means at the section master, and means for cutting off themeans responsive to the super master and-i substituting t e manual control means. Y 8. control system adapted to regulate various 'elements contributing to a common output, comprising a super master control' ler, a plurality of section'master controllers,.

means at each Asection master for controlling f the said variable elements, loading 'means for each of saidsection master controllers, the super master controller having means responsive to the fluctuations of a function of v the common output, loading means for the same and communicating` means leading from the super master controller tothe sec'- tion master controllers whereby the loadings of the-section master controllers are rendered responsiveto changes in the super master controller engendered by the fluctuations of the common output, with manual control means at the super master andsection masters, andV means for cutting, off the means rel sponsive to the requirements'at the super master and to the super master at thesection master and substituting the manual control l a l 9. In a refrulator the combination com- 7 prising a master controller, a subcontroller,

means for regulating said subcontroller and duplicate means for transmitting force from said master controller to -saidl regulating means, said regulating means being adapted to utilize the combined force of the duplicate In a regulator, the combination coming said fluid to the subcontroller, and means l opcratable by the fluid flowing through such conductors to l regulate lthe subcontroller through either one ofthe conductors acting v alone or by bioth conductors acting conjointly' with the same force as either one acting alone.

11. In a regulator, the combination comprising a master controller connected with a source of fluid under pressure and regulat- 4able to vary the pressure of said fluid, a subcontroller, duplicate conduits for the said fluid leading'from the master controller to the subcontroller, means for regulating the subcontroller, means connected vwith each of the conduits responsive to fluctuations of the pressurein the conduit with which it is con nected,` each of said responsive means normally bearing with equal force upon the said regulating means and upon failure of pressure in oneof the conduits allowing the responsive means of the other conduit to bear upon the regulator with twice the force.

12. A control system adapted to regulate various elements contributing to a common output, comprising a supermaster controller connected with a source of fluid under pressure and regulatable to vary the pressure of said Huid, a plurality of section master controllers likewise connected to asource of fluid underpre'ssure, means cooperatively relating the supermaster to the section masters to varythe fluid pressure of each section master responsively to variations of the supermaster pressure, and lines leadingV from said section masters to deliver regulatable controlling pressures therefrom.

CHARLES H. SMOOT. 

